To find the change in width of the rectangle, we need to understand the relationship between length, width, and area. The formula for the area of a rectangle is length multiplied by width (A = L * W).

Let`s assume the initial length of the rectangle is L, and the initial width is W. After increasing the length by 60%, the new length is L + (60% of L) = L + 0.6L = 1.6L.

To maintain the same area, the new width (let`s call it W`) can be calculated by dividing the initial area (L * W) by the new length (1.6L), resulting in W` = (L * W) / (1.6L) = W / 1.6.

The change in width can be calculated using the formula: Change in width = (Initial width - New width) / Initial width * 100%.

Substituting the values, the change in width = (W - W / 1.6) / W * 100% = (0.6W / 1.6) / W * 100% = 0.375 * 100% = 37.5%.

So, the correct answer